Interleukin-6 (IL-6)
Interleukin-6 (“IL-6”) is a multifunctional cytokine involved in numerous biological processes such as the regulation of the acute inflammatory response, the modulation of specific immune responses including B- and T-cell differentiation, bone metabolism, thrombopoiesis, epidermal proliferation, menses, neuronal cell differentiation, neuroprotection, aging, cancer, and the inflammatory reaction occurring in Alzheimer's disease. See Papassotiropoulos, et al. (2001) Neurobiology of Aging 22: 863-871.
IL-6 is a member of a family of cytokines that promote cellular responses through a receptor complex consisting of at least one subunit of the signal-transducing glycoprotein gp130 and the IL-6 receptor (“IL-6R”) (also known as gp80). The IL-6R may also be present in a soluble form (“sIL-6R”). IL-6 binds to IL-6R, which then dimerizes the signal-transducing receptor gp130. See Jones (2005) Immunology 175: 3463-3468.
IL-6 is a pleiotropic pro-inflammatory cytokine, which regulates the acute phase response and the transition from the innate to the adaptive immune response. IL-6 increases hepatic synthesis of proteins that are involved in the ‘acute phase response’ leading to symptoms such as fever, chills, and fatigue. It stimulates B cell differentiation and secretion of antibodies and prevents apoptosis of activated B cells. IL-6 activates and induces proliferation of T cells and in the presence of IL-2, induces differentiation of mature and immature CD8 T cells into cytotoxic T cells. IL-6 is also involved in the differentiation of Th17 cells and IL-17 production and inhibits regulatory T cells (Treg) differentiation. IL-6 also activates osteoclasts, synoviocytes, neutrophils, and other hematopoietic cells. Park, et al. (2007) Bulletin of the NYU Hospital for Joint Diseases 65 (suppl 1): S4-10; Guerne, et al. (1989) J Clin Invest. 83(2): 585-92; Houssiau, et al. (1988) Arthritis Rheum. 31(6): 784-8; Nishimotor, et al. (2006) Nat Clin Pract Rheumatol. 2(11): 619-26; Kishimoto (1989) Blood 74(1): 1-10; and Van Snick (1990) Annu Rev Immunol. 8: 253-78.
In humans, the gene encoding IL-6 is organized in five exons and four introns, and maps to the short arm of chromosome 7 at 7p21. Translation of IL-6 RNA and post-translational processing result in the formation of a 21 to 28 kDa protein with 184 amino acids in its mature form. See Papassotiropoulos, et al. (2001) Neurobiology of Aging 22:863-871.
The function of IL-6 is not restricted to the immune response as it acts in hematopoiesis, thrombopoiesis, osteoclast formation, elicitation of hepatic acute phase response resulting in the elevation of C-reactive protein (CRP) and serum amyloid A (SAA) protein. It is known to be a growth factor for epidermal keratinocytes, renal mesangial cells, myeloma and plasmacytoma cells. Grossman, et al. (1989) Prot Natl Acad Sci. 86(16): 6367-6371; Horii, et al. (1989) J Immunol. 143(12): 3949-3955; and Kawano, et al. (1988) Nature 332: 83-85. IL-6 is produced by a wide range of cell types including monocytes/macrophages, fibroblasts, epidermal keratinocytes, vascular endothelial cells, renal messangial cells, glial cells, condrocytes, T and B-cells and some tumor cells. Akira, et al. (1990) FASEB J. 4(11): 2860-2867. Except for tumor cells that constitutively produce IL-6, normal cells do not express IL-6 unless appropriately stimulated.
Elevated IL-6 levels have been observed in many types of cancer, including breast cancer, leukemia, ovarian cancer, prostate cancer, pancreatic cancer, lymphoma, lung cancer, renal cell carcinoma, colorectal cancer, and multiple myeloma. See, e.g., Chopra, et al. (2004) MJAF 160:45-49; Songur, et al. (2004) Tumori 90:196-200; Slay, et al. (1992) Cancer Research 52: 3317-3322; Nikiteas, et al. (2005) World J. Gasterenterol. 11:1639-1643; reviewed in Heikkila, et al. (2008) Eur J Cancer 44:937-945. Clinical studies (reviewed in Trikha, et al. (2003) Clinical Cancer Research 9: 4653-4665) have shown some improvement in patient outcomes due to administration of various anti-IL-6 antibodies, particularly in those cancers in which IL-6 plays a direct role promoting cancer cell proliferation or survival.
As noted above, IL-6 stimulates the hepatic acute phase response, resulting in increased production of CRP and elevated serum CRP levels. For this reason, C-reactive protein (CRP) has been reported to comprise a surrogate marker of IL-6 activity. Thus, elevated IL-6 activity can be detected through measurement of serum CRP. Conversely, effective suppression of IL-6 activity, e.g., through administration of a neutralizing anti-IL-6 antibody, can be detected by the resulting decrease in serum CRP levels.
IL-6 is believed to play a role in the development of a multitude of diseases and disorders, including but not limited to fatigue, cachexia, autoimmune diseases, diseases of the skeletal system, cancer, heart disease, obesity, diabetes, asthma, Alzheimer's disease and multiple sclerosis. See, e.g., WO 2011/066374, WO 2011/066371, WO 2011/066378, and WO 2011/066369.
A recent clinical trial demonstrated that administration of rosuvastatin to apparently healthy individuals having elevated CRP (greater than 2.0 mg/l) reduced their CRP levels by 37% and greatly decreased the incidence of myocardial infarction, stroke, arterial revascularization, hospitalization for unstable angina, or death from cardiovascular causes. Ridker et al., N Engl J Med. 2008 Nov. 9 [ Epub ahead of print].
In addition to its direct role in pathogenesis of some cancers and other diseases, chronically elevated IL-6 levels appear to adversely affect patient well-being and quality of life. For example, elevated IL-6 levels have been reported to be associated with cachexia and fever, and reduced serum albumin. Gauldie, et al. (1987) PNAS 84: 7251-7253; Heinric, et al. (1990) Biochem J. 265(3): 621-636; Zamir, et al. (1993) Metabolism 42: 204-208; Zamir, et al. (1992) Arch Surg 127: 170-174. Inhibition of IL-6 by a neutralizing antibody has been reported to ameliorate fever and cachexia in cancer patients, though improvement in these patients' serum albumin level has not been reported. Emilie, et al. (1994) Blood 84: 2472-2479; Blay, et (1992) Cancer Research 52: 3317-3322; Bataille, et al. (1995) Blood 86: 685-691.
Mucositis
Mucositis is the painful inflammation and ulceration of the mucous membranes lining the digestive tract, usually as an adverse effect of chemotherapy and radiotherapy treatment for cancer. Ridge, et al. “Head and Neck Tumors” in Pazdur R, Wagman L D, Camphausen K A, Hoskins W J (Eds) Cancer Management: A Multidisciplinary Approach. [11 Ed.] (2008). Mucositis can occur anywhere along the gastrointestinal (GI) tract. Oral mucositis is marked by inflammation and ulceration in the mouth and is a common and often debilitating complication of cancer treatment. Sonis (2004) J Supportive Oncology 2(Suppl 3): 3-8.
Oral and gastrointestinal mucositis is a toxicity of many forms of radiotherapy and chemotherapy. It has a significant impact on health, quality of life and economic outcomes that are associated with treatment. It also indirectly affects the success of antineoplastic therapy by limiting the ability of patients to tolerate optimal tumoricidal treatment. The complex pathogenesis of mucositis has only recently been appreciated and reflects the dynamic interactions of all of the cells and tissue types that comprise the epithelium and submucosa. The identification of the molecular events that lead to treatment-induced mucosal injury has provided targets for mechanistically based interventions to prevent and treat mucositis.
Historically, mucositis was thought to arise solely as a consequence of epithelial injury. It was hypothesized that radiation or chemotherapy nonspecifically targeted the rapidly proliferating cells of the basal epithelium, causing the loss of the ability of the tissue to renew itself. The atrophy, thinning and ulceration of the mucosal epithelium that is associated with mucositis was thought to be a consequence of these events. Furthermore, it was believed that the process was facilitated by trauma and oral microorganisms.
Radiation-induced mucositis was typically recognized as an ‘outside-in’ process, in which DNA strand breaks occurred in oral basal-epithelial cells. Chemotherapy-induced mucositis has mainly been attributed to basal-cell damage that results when drugs permeate to these cells from the submucosal blood supply. A role for saliva-borne chemotherapeutic agents in the induction of mucositis has been also been proposed, but not proven. Chemotherapy-induced mucositis can be further compounded by concomitant myelosuppression.
Radiation- or chemotherapy-induced mucositis is initiated by direct injury to basal epithelial cells and cells in the underlying tissue. DNA-strand breaks can result in cell death or injury. Non-DNA injury is initiated through a variety of mechanisms, some of which are mediated by the generation of reactive oxygen species. Radiation and chemotherapy are effective activators of several injury-producing pathways in endothelia, fibroblasts and epithelia. In these cells, the activation of transcription factors such as nuclear factor-κB (NF-κB) and NRF2 leads to the upregulation of genes that modulate the damage response. Immune cells (macrophages) produce pro-inflammatory cytokines, such as tumour-necrosis factor-α (TNF-α) and interleukin 6, which causes further tissue injury. These signaling molecules also participate in a positive-feedback loop that amplifies the original effects of radiation and chemotherapy. For example, TNF-α activates NF-κB and sphingomyelinase activity in the mucosa, leading to more cell death. In addition, direct and indirect damage to epithelial stem cells results in a loss of renewal capacity. As a result, the epithelium begins to thin and patients start to experience the early symptoms of mucositis.
Mucositis is observed during chemotherapeutic or radiation treatment of many different cancers including head and neck cancer, multiple myeloma, colorectal cancers, Because of the problems caused by mucositis which may preclude further radiation or chemotherapy and also impede nutrition because of the discomfort caused by mucositis during swallowing and digestion
The most common symptoms of mucositis include redness, dryness, or swelling of the mouth, burning or discomfort when eating or drinking, open sores in the mouth and throat, abdominal cramps, and tenderness or rectal redness or ulcers. Essentially mucositis involves the inflammation of the lining of the mouth and digestive tract, and frequently occurs in cancer patients after chemotherapy and radiation therapy. The cheek, gums, soft plate, oropharynx, top and sides of tongue, and floor of the mouth may be affected, as well as the esophagus and rectal areas. Along with redness and swelling, patients typically experience a strong, burning pain.
Oral and gastrointestinal (GI) mucositis can affect up to 100% of patients undergoing high-dose chemotherapy and hematopoietic stem cell transplantation (HSCT), 80% of patients with malignancies of the head and neck receiving radiotherapy, and a wide range of patients receiving chemotherapy. Alimentary tract mucositis increases mortality and morbidity and contributes to rising health care costs. Rubenstein, et al. (2004) Cancer 100(9 Suppl): 2026-46.
For most cancer treatment, about 5-15% of patients get mucositis. However, with 5-fluorouracil (5-FU), up to 40% get mucositis, and 10-15% get grade 3-4 oral mucositis. Irinotecan is associated with severe GI mucositis in over 20% of patients. 75-85% of bone marrow transplantation recipients experience mucositis, of which oral mucositis is the most common and most debilitating, especially when melphalan is used. In grade 3 oral mucositis, the patient is unable to eat solid food, and in grade 4, the patient is unable to consume liquids as well. Rubenstein, et al., (2004) Cancer 100(9 Suppl): 2026-46.
Radiotherapy to the head and neck or to the pelvis or abdomen is associated with Grade 3 and Grade 4 oral or GI mucositis, respectively, often exceeding 50% of patients. Among patients undergoing head and neck radiotherapy, pain and decreased oral function may persist long after the conclusion of therapy. Fractionated radiation dosage increases the risk of mucositis to >70% of patients in most trials. Oral mucositis is particularly profound and prolonged among HSCT recipients who receive total-body irradiation. Rubenstein, et al., (2004) Cancer 100(9 Suppl): 2026-46.
Although there are factors that increase the likelihood and severity of mucositis, there is no reliable manner to predict who will be affected. Not only is mucositis more common in elderly patients, the degree of breakdown is often more debilitating. The severity of mucositis tends to be increased if a patient exercises poor oral hygiene or has a compromised nutritional status. A preexisting infection or irritation to the mucous membrane may also result in a more severe case of mucositis.
The types of drug used to treat cancer and the schedule by which they are given may influence the risk of developing mucositis. Doxorubicin and methotrexate, for example, frequently cause mucositis. The chemotherapy agent fluorouracil does not usually severely affect the mucous membranes when administered in small doses over continuous intravenous (IV) infusion. When the schedule is adjusted so that a higher dose is given over a shorter period of time (typically over five days), fluorouracil can cause very severe, painful, dose-limiting cases of mucositis. Patients undergoing treatment with high-dose chemotherapy and bone marrow rescue often develop mucositis.
In addition, mucositis also tends to develop in radiation therapy administered to the oral cavity, or in dosages that exceed 180 cGy per day over a five-day period. Combination therapy, either multiple chemotherapy agents or chemotherapy and radiation therapy to the oral cavity, can increase the incidence of mucositis.
Currently there is no real cure for mucositis, treatment is aimed at prevention and management of symptoms. Mucositis typically resolves a few weeks after treatment as the cells regenerate, and treatment cessation is only occasionally required. In some cases, drug therapy will be altered so that a less toxic agent is given.
Patients at risk for mucositis should be meticulous about their oral hygiene, brushing frequently with a soft toothbrush and flossing carefully with unwaxed dental floss. If bleeding of the gums develops, patients should replace their toothbrushes with soft toothettes or gauze. Dentures should also be cleaned regularly. Patients should be well-hydrated, drinking fluids frequently and rinsing the mouth several times a day. Mouthwashes that contain alcohol or hydrogen peroxide should be avoided as they may dry out the mouth and increase pain. Lips should also be kept moist. Physical irritation to the mouth should be avoided. If time permits, dental problems, such as cavities or ill-fitting dentures, should be resolved with a dentist prior to beginning cancer treatment. Patients are generally more comfortable eating mild, medium-temperature foods. Spicy, acidic, very hot or very cold foods can irritate the mucosa. Tobacco and alcohol should also be avoided.
Hospital personnel and the patients themselves should inspect the mouth frequently to look for signs and symptoms of mucositis. Evidence of mucositis (inflammation, white or yellow shiny mucous membranes developing into red, raw, painful membranes) may be present as early as four days after chemotherapy administration. Sodium bicarbonate mouth rinses are sometimes used to decrease the amount of oral flora and promote comfort, though there is no scientific evidence that this is beneficial. Typically, patients will rinse every few hours with a solution containing ½ teaspoon (tsp) salt and ½ tsp baking soda in one cup of water.
Pain relief is often required in patients with mucositis. In some cases, rinsing with a mixture of maalox, xylocalne, and diphenhydramine hydrochloride relieves pain. However, because of xylocalne's numbing effects, taste sensation may be altered. Worse, it may reduce the body's natural gag reflex, possibly causing problems with swallowing. Coating agents such as kaopectate and aluminum hydroxide gel may also help relieve symptoms. Rinsing with benzydamine has also shown promise, not only in managing pain, but also in preventing the development of mucositis. More severe pain may require liquid Tylenol with codeine, or even intravenous opioid drugs. Patients with severe pain may not be able to eat, and may also require nutritional supplements through an I.V. (intravenous line).
A treatment called cryotherapy has shown promise in patients being treated with fluorouracil administered in the aforementioned five-day, high-dose schedule. Patients continuously swish ice chips in their mouth during the thirty-minute infusion of the drug, causing the blood vessels to constrict, thereby reducing the drug's ability to affect the oral mucosa.
Chamomile and allopurinol mouthwashes have been tried in the past to manage mucositis, but studies have found them to be ineffective. Biologic response modifiers are being evaluated to determine their possible role in managing mucositis. Recent studies using topical antimicrobial lozenges have shown promise as well, but more research is needed. Patients with multiple myeloma receiving chemotherapy (dexamethasone and melphelan) and autologous stem cell transplantation (ASCT) who were in addition administered an anti-IL-6 antibody (BE8) had reduced CRP levels and a significant reduction in fever as well as reduced onset and severity of mucositis. Rossi, et al. (2005) Bone Marrow Transplantation 36: 771-779. Particularly, the mucositis in the treated patients was a lower grade of toxicity requiring no morphine infusion as compared to patients not receiving the anti-IL-6 antibody. Also, gastrointestinal mucositis symptoms such as diarrhea were reduced and quality of life was improved as evidenced by better oral intake of nutrition and daily activity.
Therefore, there is a strong need in the art for improved methods of treating and preventing mucositis, both oral and gastrointestinal mucositis, as this condition compromises the efficacy of chemotherapy or radiation cancer treatments as well as adversely affecting the quality of life of cancer patients because of the extreme pain and discomfort caused by this condition. The invention described herein provides compositions comprising anti-IL-6 antibodies and antibody fragments thereof, and methods of use which may be used to treat IL-6 related conditions.